1. Technical Field
The present invention relates to a display device and an electronic apparatus including the display device.
2. Related Art
In recent years, a technique of incorporating an optical sensing function in a liquid crystal display device employing a thin film transistor, in particular, has been developed (refer to Japanese Unexamined Patent Application Publication No. 2006-118965, for example) in order to obtain the following advantages using optical sensors. (1) Power consumption is reduced and image quality is improved by controlling luminance, for example, by measuring external light. (2) The luminance and chromaticity is controlled by measuring backlight. (3) The optical sensors are used as a touch key so as to detect a position of a finger or a light pen. Examples of the optical sensors include thin-film transistors, PIN (p-intrinsic-n) diodes, and PN diodes. The optical sensors preferably have light-receiving sections formed of silicone thin films, and a process of fabricating the optical sensors are preferably performed simultaneously with a process of fabricating switching elements which are formed of silicon thin films and which are used for display so that increase of fabrication cost is suppressed.
In terms of accuracy of measurement of a light intensity and design, the optical sensors are preferably disposed near a display region of a display device. However, in a liquid crystal display device incorporating a driving circuit, it is difficult to dispose the optical sensors in an inner side relative to the driving circuit. Furthermore, when the optical sensor is disposed near the display region, the optical sensors are likely to be influenced by electrical noise generated by driving the display region, and are likely to be influenced by stray light emitted from the display region. Therefore, there arises a problem in that sensing accuracy of the optical sensor is deteriorated. This problem is remarkable for the liquid crystal display device which performs common potential inversion driving.